Philips TDA2611A - Manual (Page 4)

November 1982 4
Philips Semiconductors Product specification
5 W audio power amplifier TDA2611A
Fig.2 Power derating curves.
HEATSINK EXAMPLE
Assume V
P
=
18 V; R
L
=
8
Ω
; T
amb
=
60
°
C maximum; T
j
=
150
°
C (max. for a 4 W application into an 8
Ω
load, the
maximum dissipation is about 2,2 W).
The thermal resistance from junction to ambient can be expressed as:
Since R
th j-tab
=
11 K/W and R
th tab-h
=
1 K/W, R
th h-a
=
41
−
(11
+
1)
=
29 K/W.
R
th j-a
R
th j-tab
R
th tab-h
R
th h-a
150 60 –
2 2
,
---------------------- 41 K/W. = = + + =